Sgificaticn



} (No Model.) 3 Sheets-Sheet 1.

G. G. BURKE.

MULTIPLEX TELEGRAPH. No. 313,298. Patented Mar. 3, 1885.

lil'n l WITNESSES: 51"

N. PETERS. Pholo-Lflhogmphcr. wmwn mm D. 6.

Im} INVENTOR C/zarles GJfiake,

(No Model.) 3 Sheets-Sheet 2.

U. G. BURKE.

MULTIPLEX TELEGRAPH.

No. 313,298. Patented Mar. 3, 1885.

WITNESSES IN VENTOR @M BY Charles Glhu'k'e ATTORNEYS N. PETEH$ Plwwunm m ner, Washizlglou. n. c.

(No Model.) 3 Sheets-Sheet 3.

0. G. BURKE.

MULTIPLEX TELEGRAPH. I No. 313,298. Patented Mar. 3, 1885.

igg gg WITNESSES: I INVENTOR fidd BY G za/fies 6113x0176 W a) ATTORNBYS UNrTnn STaTns PaTsri T CHARLES G. BURKE, OF RICHMOND HILL, HEW JOEY.

MULTiPLEX TELEG RAPH.

Application filed April 9, 1854.

To ml] whom it may concern-.-

Be it known that I, Ormnrms G. BURKE, a citizen of the United States, residing at Richmond Hill, in the county of Queens and State of New York, have invented certain new and useful Improvements in Multiple Telegraphy, of which the following is a specification.

My invention relates to the class of telegraphic apparatus designed to transmit over a single main-line conductor in the same three tion two or more messages with equal facility and with as great rapidity as that with which the transmission of a single message is accomplished. Very many and various forms of apparatus have been devised aiming to accomplish this result, and these have usually been organized either to transmit electricimpulses or currents of different characteristics simultaneously, and to cause such impulses or currents to actuate each a corresponding receiving-instrument, or else to connect the respective terminals of the main-line conductor successively and simultaneously with the individual conductors of two series of subsidiary or branch conductors which respectively in clude the transmitting and the receiving instruments. The former of these classes of apparatus requires an accurate and a careful adjustment ofthe line and of the receiving apparatus, and the second class of apparatus is with difficulty maintained in practical working condition, owing to the dil'liculty of maintaining in synchronism the devices employed at the respective terminals of the line for con trolling the eircuit-connections. Moreover, the necessary depreciation in electrical energy which is involved in subdividing the electric current, so that it will traverse the several branch circuits in succession, necessarily greatly increases the ense of operating the last-named system.

The object of my invention is to so organize the apparatus that'the several transmittinginstrnments shall be in condition to send to line the appropriate signals or impulses adapted to produce the same, each at a different moment, and to cause the moments at which the several instruments are thus in condition to transmit to be repeated with such frequency that no instrumentshall be rendered inoperative during a greater period than that which must necessarily exist between the successive GEFICATICN forming part; of Letters Patent No. 318,298, dated March 3, T835.

(X0 model.)

signatproducingimpulses. Thetransmittinginstruments which are thus successively connected with the main line are organized each to transmit currents or impulses of different characteristics. The receiving -instrurnents respectively corresponding thereto are all normally included in the main line, and they are organized to respectively respond to the im pulses transmitted by the appropriate transmitting-instruments.

In carrying out my invention I prefer to employ two or more key-boards, each of which is constructed with an annular series of keys I ing arms and to each other that at the mo ment any one of the circuit-closing arms is passing bencatha key upon its board the other circuit-closing arms shall be passing across the spaces intervening between two keys of their respective key-boaus. The keys are therefore preferably arranged at such distances apart that in the space intervening between two successive keys a number of keys equal to one less than the number of keyboards which it is desired to employ could be inserted. Thus, if it is desired to employ four transmitters. and to provide each key-board with, say, twenty six characters, then con sidering, for convenience, that each key-board be divided by radial lines into one hundred and four equal sections, and these sections be numbered alike in each board. a key would board a key would be placed in each fourth l line through the influence of currents of in section; but no two keys upon different boards would be located in corresponding sections. The circuit-closing arms are preferably driven at the same velocities by a motor-shaft common to all, and they are arranged so that they will pass beneath the consecutive divisions of the boards at the sametime. Thekeys themselves are preferably constructed to automatically transmit, when struck by the circuit-closing arms,impulses adapted to produce the dots and dashes representing the characters of the Morse alphabet; and to this end they are preferably constructed in the following manner: Each key consists of a vertically-movable pin, carrying a wide flattened head. Beneath this head are placed one or more contact-pins,wl1ich are adapted to be forced downward into the path of the circuit-closing arm by the depression of the key, and to stand in the path of such arm until struck by the same. Each pin may be thus moved upward independently of the other pins which may be applied to the same key. The contact of the circuit-closing arm with the pin not only forcesthe latter upward out of its path, but also causes an impulse to be transmitted to line having a characteristic appropriate to the key-board. An individual pin thus depressed is designed to transmit an impulse corresponding to the dot employed in the Morse alphabet. hen two pins are so located that the one is struck immediately after the other, a Morse dash will be transmitted. The pins, therefore, which are applied to each key are arranged in a manner to occasion a dot or a dash, or a succession of the same, corresponding to the Morse representation of the different characters.

The respective receiving-instruments are, as has already been stated, organized to respond to those currents or impulses only which are transmitted by the corresponding transmitting device. Thus if, forinstance, there be four key-boards employed and the first key-board transmits positive impulses having a given strength, the second negativeimpulses having an equal strength, the third and fourth positive and negative impulses, respectively, of an increased strength, then the four corresponding receivirig-instruments should be organized to respectively respond to the four classes of currents thus produced. This may be aceonr plished in different ways; but in practice I prefer to place four polarized relays in the normal circuit of the main line and to adjust the first to respond only to the positive and the second to the negative impulses of the lesser strength, and the third and fourth instruments to respond only to thepositive and to the negative impulses, respectively, of the increased strength.

Some means are necessary for preventing the first and second instruments from responding to the currents of increased strength. This may be accomplished by causing them to l l l l l creased strength; or they may be provided with armature-levers which serve to close local circuits, in which are included sounders or othersuitable receiving-instruments, and to interrupt the same when actuated by the currents ofincrcascd strength, by overcoming the retractile force exerted upon supplemental contact-levers included in'the local circuits.

Various other methods of organizing the receiving instruments may be adopted, as found convenient.

In the accompanying drawings, Figure 1 is a diagram illustrating the general organiza tion of apparatus and circuits embodying my invention, and Fig. 2 is a plan view, and Fig. 3 is a vertical transverse section, of one of the keyboards. Fig. 4 is an enlarged view of one oft-hekeys, showing the disposition ofthe pins. Fig. 5 illustrates a modification in the organization of the apparatus.

Referring to these drawings, A, A, A, and

A represent four transmitting key-boards, which are designed to transmit impulses from four batteries, O, 0 O, and 0, respectively, upon a main line, L. The key-boards are pro vided each with an annular series of keys, as shown at B, and these keys are all in connection with the main line through their supporting-plates a. The circuit-closing arms are revolved beneath the lower extremities of the corresponding keys at equal velocities by means of a shaft, D, with which they are connected by means of suitable gear-wheels, c. The circuit-closing arms 13, B-, B, and B are respectively provided with contact-brushes b, b", and I)", through which they are placed in electrical connection with their respective batteries, 0, O 0, and O. The battery 0 has a given strength, which for convenience may be considered as capable of producing a current having a strength of 1.2,L[ld the positive pole of this battery is connected through the conductor 1 with the brush I). The battery O is of the same strength as the battery 0, but its negative pole is connected with the brush b by a conductor, 2. The batteries 0 and 0" have each a strength greater than the battery 0 or O", and are capable of producing a current of, say, a strength represented by 2.v The positive pole of the battery 0 is connected with the brush b" by a conductor, 3, and the negative pole of the battery O is connected by a conductor, 1-, with the brush b. The remaining poles of the batteries 0, 0*, O", and O are connected with the earth at G. G G, and G, respectively. If, therefore, a key upon the board A be struck by the contactarm G, a positive impulse of a strength 1m will be transmitted to line, and in like manner the keys upon the board A will transmit negative impulses of the same strength. The keys of the boards A and A will, respectively, transmit impulses of twice the strength, and of positive and of negative polarity, respectively. The keys may be constructed be automatically disconnected from the main to transmit impulses of different lengths or ICO other characteristics; but I prefer to provide key-boards, and they preferably extend be upon each board one key for each letter or other character which it may be desired to employ, and to construct them to severally transmit the impulses or currents employed in the Morse alphabet for indicating those characters. For this purpose each key consists of a movable support, f, having an enlarged head, f. The support f is preferably surrounded by a spring, f which normally holds the key up in the position shown in the drawings. The key may, however, be constructed of snfficientlength to project into the path of the contact-arms when depressed, and to be automatically returned by the contact of the arm therewith in the same manner as the pins, which will be hereinafter described. Beneath the head of each key is placed one or more circuitclosing pins, g. These pins are normally held out of the paths of the circuit-closing arms by springs h, which enter annular grooves h formed therein. \Vhen, however, any key is pressed downward, the pins beneath the same are forced into the path of the corresponding circuit-closing arm, and they remain in such position until struck by the circuit-closing arm. The lower extremities of the pins are rounded, so that when struck by the circuit-closing arm they will be automatically raised to their normal positions. Each pin is, however, movable independently of the others, so that only the particular pin which is struck by the circuit-closing arm will be raised. The contact of the arm not only raises the pin, but serves, by completing the circuit-connections, to transmit to the line an impulse of a strength and polarity dependent upon the battery with which the arm is connected. The duration of the impulses thus transmitted will depend upon the rate of revolution of the circuit-closing arms and upon the extent of the contact-surfaces. In practice I prefer to so adjust these that the contact with a single pin will produce an impulse equivalent to that usually employed for producing or indicating a Morse dot. If, however, two pins should be so located that the arm makes contact with the second before it leaves the first, there would be produced an impulse in length equivalent to a Morse dash. It will be understood that to produce the various i1npulses representing the Morse alphabet, or, in fact, any other desired arbitrary code, it will be necessary only to properly combine the pins in applying them to a key. Thus, if it is desired to produce a signal consisting of a dash and a dot separated by a space, three pins would be arranged in the path of the circuit-closing arm in such manner that the second would be struck by the arm before the arm had passed out of contact with the first, while the third would be struck after the arm had passed out of contact with the second.

The pins, when one is designed to succeed another for the purpose of producing a dash, are preferably placed in different circles, or

at different distances from the center of the yond each other a slight distance, so that a radial line touching the edge of one pin would cut the adjacent pin. *This construction is desirable for the purpose of insuring that there shall be no interval between the two contacts when it is desired to form a dash, 011 account of the rounded surfaces which the contact-pins present to the arm, and it is also desirable for convenience in construction. It will be understoood, therefore, that in effect the dash formed by two pins may not in length be equal to two full dots, but the length produced will be found sufficient to serve all the requirements. The space which separates two keys may be less than the contact-surfaces ofthe keys, if it is so desired.

The arrangement of the pins employed in the individual keys will now be readily understood without further describing the keys in particular.

In the drawings I have represented keys corresponding to the twenty-sixletters of the alphabet; but the series may be extended as found desirable for the purpose of including marks of punctuation and other characters.

Considering now the arrangement of the boards with reference to each other, each board may be iegarded as being divided in this instance into one hundred and four equal segments by radial lines, as indicated at t t t,

Considering the spaces thus marked off to be numbered from one to one hundred and four in each board, and that the circuit-closing arms stand simultaneously beneath correspond segments, a keyfor instance, the key marked "A in the board A-is located in the first segment. In the keyboard A the corresponding key,A,is located in the second segment, while in the third board, A, it occupies the third segment, and in the board A* the fourth segment. The second letter of the series, say N, is located in the fifth segment of the board A, the sixth segment of the board A-,the seventh of the board A, and the eighth of the board A", and this same order of arrangement is carried out throughout the entire series olletters or other characters which may be employed. It will now be understood that no two of the arms can simultaneously act to transmit an impulse, for the reason that at no time are two contact-arms passing beneath a key, but the arm 0 passes beneath a key, B, the arm 0- then passes beneath a key, B", then the arm 0 beneath a key, B, and finally the arm 0 passes a key, B. The operation is then repeated with reference to the succeeding key of the series. The time, however, which elapses while any arm is passing from one key to the next upon its board is practically of no greater duration than it is desirable should elapse between the transmission of two successive letter-signals, so that no appreciable time is lost in the one board by reason of the intervention ofthe keys upon the other boards.

In operating the instruments the keys may be pressed down as fast as may be desired in advance of the circuit-closingarms. The appropriate. signals will be automatically trans mitted and the pins raised when the arm arrives at the keys so depressed. The only precaution which it is necessary for the transmitting-operator to observe in selecting the keys is not to pass so far in advance of the arm as to overtake it.

In practice it will be found advantageous to arrange the characters upon the key-boards in a succession, which is found to bring the letters or characters most frequently succeeding each other in the class of communication to which the instruments are applied in succession. Such an arrangement is indicated upon the respective hey-boards.

It remains now to describe in what manner the impulses thus transmitted are employed at the receiving-station for producing the proper signals or records.

In the drawings four reccivinginstruments are representedlli, M M and M"-and these are respectively designed to respond to the impulses transmitted by the ion r keyboards A, A", A, and A. The receiving-instruments are all included in the main-line conductor, and they are preferably each constructed with a supplemental polarizing-coil, m, which is so connected in a local circuit, Z, including a battery, 0, that the core it receives a normal polarization of a given character. The polarization thus caused is not, however, SllffiClGllh to overcome the retractile l'orce exerted upon the armature-levers p of the instruments, and it is only when this magnetism is increased by a current of the proper charactor from the main line that the armature will be moved toward the poles of the mag net.

The instrument Ill is so organized that its armature will respond to a positive current of the strength transmitted by the key-board A, and it is evident that it will not 'espond to a current from the board 13*, for the reason that such a current will be of the character tending to neutralize the magnetism produced by the action of the local battery 0. The armature of the instrument M will, however, rospond to such an impulse, for the reason that the magnetism produced by its local battery is of the same character as that occasioned by the current from the main line. The instruments M" and M" are in like manner constructed to respond to currents from the transmitters A and A, respectivelythat is to say, to positive and to negative impulses of increased strength.

t will be evident, however, that some means must be provided for preventing the receivinginstrun'ients BI and H from responding to the stronger currents thus transmitted. This may be accomplished by causing the armature-levers p and p to complete local circuits when drawn forward by making contact with supplemental levers r and 2", respectively. A sounder, S, is included in each of these two local circuits, together with a battery, 0 0". The respective circuits of these batteries are completed through the supplemental levers), when the corresponding electroanagnet is vitalized by a current having the strength represented by 100, and the corresponding sounders will therefore be actuated. \Vhen, however, either armature is drawn forward by a current of the strength represented by 20:, then the retractile force applied to the supplemental lever 1' will also be overcome, and the local circuit will be interrupted at the restingstop 1 of the supplemental lever. Theinstruments M and II also preferably act to complete local circuits through sounders S and S, respectively, in the same manner, excepting that it will not be necessary to employ supplemental contact-levers with these instruments, unless it is desired to extend the number of instruments beyond four, in which casetheinstruments M" and M should be constructed in substantially the same manner as described with reference to the instruments M and M In Fig. 5 I have illustrated another method which maybe employed for the purpose of rendering the instruments M and M inoperative when currents of sullieient strength to actuate the instruments M or M" are transmitted. This consists in normally completing the main line connections from the instrument hi to the instrument M through the armature of a circuit-controlling clectro-magnet, It, and its resting contact-stop a This electro-magnet responds to both positive and negative currents. The armature of the electro-lnagnet R is adjusted so that it will not respond to cur rents ot' the strength employed for actuating the instruments ill and ill, but it will respond to currents of increased strength, and by drawing its armature into its forward position it acts to interrupt the connections normallyexisting between the conductor leading from the instrument M to the instrument M, and to connectthat conductor, through a stop, if, and contact-spring a, with the earth at G". The instrument In? or In? will then respond accordingly as it is a positive or a negative current which is being transmitted; but neither of the instruments M and M will respond, being out of circuit.

Various other methods of rendering the several instruments responsive only to the currents transmitted by the particular transmitters to which they correspond may be adopted, as found advantageous; but those which have been described will be suilicient to fully illustrate the invention.

It is evident that the nun'iber of transmit ting and receiving instruments which may be employed is not limited to four; but that number may be extended without departing from the principle of the invention.

In another application for Letters Patent, filed by me Illarch I8, 1884-, Serial No. Ethic, and entitled Improvementin Printing Telegraphs, I have shown and described certain organizations of apparatus which in some particulars resembles the apparatus and method of operating the same shown and ICC IIC

described in this present application, and I do not thereforeherein claim anything shown, described, and claimed in the said other application and not specifically claimed herein.

I claim as my invention:

1. The combination, substantially as hereinbefore set tort-h, of a series of transmittinginstruments, each of which is organized to transmit currents or impulses having a dis tinctive characteristic, means, substantially such as descri bed,for causing such instruments to be successively and at regularly-recurring periods placed in condition to transmit, and a series of receiving-instruments respectively responding to the currents transmitted by the several transmitting-instruments.

2. The combination, substantially as hereinbefore set forth, of a series of transmittinginstrurnents, a series of receiving-instruments respectively responding to the currents or impulses transmitted by said transmittiuginstruments, and means, substantially such as described, for placing said transmitting-instruments successively and at regularly-recurring periods in condition to t 'ansmit.

'3. The combination, substantially as hereinbefore set forth, of a main line, a series of transmittirig-instruments,a series of receivinginstruments normally included in the circuit of said main line, and respectively organized to respond to the currents or impulses occasioned by said transmittinginstruments, and means for placing said transmitting-iustruments one at a time and successively in condition to transmit.

4:. The combination, substantially as hereinbefore set forth, of two or more series of transmittingkeys, a circuit-closing arm applied to each of said series, means for causing said circuit-closing arms to pass across the paths of the individual keys in the corresponding series in succession, and across the paths of the keys of the different series at different times, and a series of receiving-instruments respectively responding to the different series of transmittingkeys.

The combination, substantially as hereinbefore set forth, of two or more series of transmitting-keys, two or more circuit-closing arms moving in unison with each other and passing across the paths of the keys of said series respectively at different times, means for causing such keys when forced into the path of the corresponding circuit-closing arm to transmit an impulse, current, or group of the same having a distinctive characteristic, and 21V series of receiving iustrui'ncnts respectively responding to the currents, impulses, or groups of the same having such distinctive characteristics.

6. The combination, substantially as hereinbefore set forth, of a series of transmittinginstruments, each of which is constructed with a series of transmitting-keys which are re spectively constructed to transmit an electric current, impulse,or a group of currents or impulses designed to respectively correspond to the characters designated by an arbitrary code, a series of receiving-instruments respectively designed to respond to the currents or impulses transmitted by the respective series of transmittirig-keys, and means, substantially such as described, for placing said series of transmitting-keys successively in connection with said receiving-instruments.

'7. A telegraphic transmitter consisting of a circuit-closing arm, a series of keys, one or more contact-pins applied to each of said keys, which pins are 'auscd to be projected into the path of said circuit-closing arm by actuating said key, and means for causing said circuit-closing arm to force each of said pins out of its path independently of the other pins.

8. The combination of a circuit-closing arm, a series of keys respectively corresponding to different letters, iigures, or other characters, and contact-pins applied to said keys, which pins are constructed to be forced into the path of said circuit-closing arm by the action of the key to which they are applied, and are arranged to transmit by the contact of the arm therewith a signal representing the character assigned to the k ey, according to a prearranged code.

9. The combination, substantially as hereinbefore set forth. of a circuit-closing arm, contact-pins applied to said arm, and which are arranged in groups adapted to transmit electric currents, or impulses or groups of currents or impulses designed to represent different characters according to a prearranged code, and means applied to each ofsaid groups for forcing the same into the path of said arm.

10. In a transmitter for electric telegraphs, a circuit-closing arm, key designed to represent a given character, and a series of contact-pins adapted to be forced into the path of said arm by said key, which pins, by the contact of said arm therewitl1,act to transmit a signal representing the character assigned to the key, and which are independently moved out of the path of said arm.

11. The combination, substantially as hereinbefore sot fortlnofa revolving circuitclosing arm and a lransmittirig-key consisting of a series of independentlyanovable contact-pins, certain of which are so arranged that the circuit-closing arm will pass across the path of one of the pins before it is out of the path of the preceding pin, substantiallyas described.

12. In a transmitter for electric telegraphs, the combination, substantially as hereinbefore set forth,with a circuit-closing ari'n,ofa movablekey and one or more independently-movable contact-pins, and a friction-spring applied to each of said pins for normally retaining the same out of the path of said circuitrlosing ilrl'lll.

13. The combinatiou,substantiallyashereinbefore set forth, of two or more independentlymovable contact-pins, ,having the grooves h, the springs h applied to said pins, and means for actuating said pins simultaneously.

14. The combination, substantially as hereinbefore set forth,with a series of transmittinginstruments each having a series of transmitting-keys and a circuit-closing arm, of means, substantially such as described, for moving each of said circuit-closing arms across the ,paths of the individual keys in the series to which it is applied successively, and at a T110- nient when the remaining circuit-closing arm or arms are passing across the space interverr ing between two keys.

15. The combination, substantially as hereinbefore set forth, with a mainline, a series of transmittirig-instruments, means, substantially such as described, for placing them in condition to transmit in succession,and means, substantially such as described,for causing said 

